feat: add simplified OR when rhs or lhs is all 1s

acvm-repo/acir_field/src/generic_ark.rs

@@ -32,7 +32,6 @@ pub trait AcirField:
 
     fn is_zero(&self) -> bool;
     fn is_one(&self) -> bool;
-
     fn pow(&self, exponent: &Self) -> Self;
 
     /// Maximum number of bits needed to represent a field element

compiler/noirc_evaluator/src/ssa/ir/dfg/simplify/binary.rs

@@ -62,6 +62,16 @@ pub(super) fn simplify_binary(binary: &Binary, dfg: &mut DataFlowGraph) -> Simpl
 
     let lhs_is_one = lhs_value.is_some_and(|lhs| lhs.is_one());
     let rhs_is_one = rhs_value.is_some_and(|rhs| rhs.is_one());
+    let lhs_is_max = if lhs_type.is_unsigned() {
+        lhs_value.is_some_and(|lhs| lhs == lhs_type.max_value().unwrap())
+    } else {
+        false
+    };
+    let rhs_is_max = if rhs_type.is_unsigned() {
+        rhs_value.is_some_and(|rhs| rhs == rhs_type.max_value().unwrap())
+    } else {
+        false
+    };
 
     match binary.operator {
         BinaryOp::Add { .. } => {
@@ -254,6 +264,11 @@ pub(super) fn simplify_binary(binary: &Binary, dfg: &mut DataFlowGraph) -> Simpl
             if lhs == rhs {
                 return SimplifyResult::SimplifiedTo(lhs);
             }
+
+            if lhs_type.is_unsigned() && (lhs_is_max || rhs_is_max) {
+                let max = dfg.make_constant(lhs_type.max_value().unwrap(), lhs_type);
+                return SimplifyResult::SimplifiedTo(max);
+            }
         }
         BinaryOp::Xor => {
             if lhs_is_zero {

compiler/noirc_evaluator/src/ssa/ir/types.rs

@@ -85,6 +85,22 @@ impl NumericType {
     pub(crate) fn is_unsigned(&self) -> bool {
         matches!(self, NumericType::Unsigned { .. })
     }
+
+    pub(crate) fn max_value(&self) -> Result<FieldElement, String> {
+        match self {
+            NumericType::Unsigned { bit_size } => {
+                if *bit_size == 128 {
+                    Ok(FieldElement::from(u128::MAX))
+                } else {
+                    Ok(FieldElement::from(2u128.pow(*bit_size) - 1))
+                }
+            }
+            NumericType::Signed { bit_size } => Ok(FieldElement::from(2u128.pow(*bit_size) - 1)),
+            NumericType::NativeField => {
+                Err("Cannot get max value for native field type".to_string())
+            }
+        }
+    }
 }
 
 /// All types representable in the IR.